Portable radio receivers, such as pagers, are typically carried by users for the purpose of receiving messages when away from a computer or telephone. Generally, a radio receiver announces reception of a message to the user by generating an alert, such as an audible tone or visible presentation. The radio receiver also usually includes a display device, such as a liquid crystal display, such that the user can read the message, either automatically or in response to manual manipulation of controls accessible from the exterior of the radio receiver. The message is typically stored for a finite length of time so that the user can re-read the message or postpone reading the message until a later time.
Recently, information service providers have implemented communication systems in which information relating to a particular topic is transmitted to a radio receiver when the user of that receiver has subscribed to the service. By way of example, a user can subscribe to a financial service which provides up-to-date information of financial interest. Additionally, a user can subscribe to a sports news service for providing information about sports events, such as baseball or football games. In such a situation, incoming messages usually replace previous messages about the same topic in the memory such that the user is not confused by conflicting information. For instance, when the radio receiver receives an updated score for a particular game, any previously received score for that game is generally discarded so that the user does not mistake the outdated, previous score for the current score. Similarly, incorrect, outdated financial information, such as a stock price, is replaced with current information to keep the user informed of the latest developments in that area. However, there could be instances when the user would benefit from the ability to refer back to information concerning a particular topic even when more recent information regarding that topic has been received.
Thus, what is needed is a method and apparatus for selectively retaining messages about a particular topic such that the user can later refer to retained messages even when more recent messages have been received.